Recently, I have been contacted by a small group of lean, pre-diabetic vegans. I had never heard of thin vegans developing pre-diabetes; it turns out that it’s not uncommon for lean people to develop pre-type-2 diabetes.

Here is an article by Susan Papuga, one of the people who contacted me, who has researched the topic thoroughly. If you aren’t familiar with the normal references for the numbers discussed below, please see Diabetes: Tests and Diagnosis from Mayo Clinic.

Pre-Type 2 Diabetes and Lean Vegans

by Susan Papuga

The majority of people with type 2 diabetes are overweight and suffer from hyperglycemia (high blood sugar) due to insulin resistance. However, there is also a condition in which thin people suffer from hyperglycemia. Few studies have been done on lean diabetics and are primarily on Asian populations. Many of these studies have found that lean type-2 diabetics are suffering from a deficiency of the insulin-producing beta cells rather than from insulin resistance. An even smaller subset rarely mentioned are lean vegans with high blood glucose; further research is needed to determine the cause of their pre-diabetes or diabetes.

The International Diabetes Foundation has developed a document, Guideline for Management of Postmeal Glucose (PDF), which states, “Although control of fasting hyperglycaemia is necessary, it is usually insufficient to obtain optimal glycaemic control. A growing body of evidence suggests that reducing postmeal plasma glucose excursions is as important, or perhaps more important for achieving HbA1c goals.” Their recommendation is that two-hour postmeal (also known as postprandial) plasma glucose should not exceed 140 mg/dl (7.8 mmol/l) as long as hypoglycemia is avoided.

In order to meet that goal for a lean vegan who is pre-diabetic or diabetic, careful consideration needs to be paid to diet. One challenge is how to prevent postprandial spikes while reducing carbohydrate and still maintaining adequate body weight. The Eco-Atkins diet can be an effective path to follow with higher fat and protein consumption from nuts, seeds, avocados, soy foods, and seitan–all helping to provide needed calories. Carbohydrate should be chosen wisely, emphasizing high fiber and low glycemic foods.

The Guideline further states, “Self-monitoring of blood glucose should be considered because it is currently the most practical method for monitoring postmeal glycaemia.” For a lean vegan, this is an important step in taming impaired glucose metabolism. For a few in our group of lean vegans, our fasting glucose was only slightly elevated while an HbA1c test and/or postprandial glucose identified pre-diabetes.

My first indication of impaired glucose metabolism was during a routine lab which showed a slightly elevated fasting glucose of 101. I started testing my fasting and postmeal glucose at home and mentioned to my doctor that I was seeing some high numbers for postmeal, up to 185. A person with normal glucose metabolism rarely goes over 140 postprandial. An oral glucose tolerance test confirmed a pre-diabetes diagnosis, and then began my journey to find a way to lower those numbers while eating a healthy vegan diet.

Personally, I’ve had success at keeping my fasting glucose under 100 mg/dl and postprandial glucose under 140 mg/dl with a diet similar to Eco-Atkins. I found that the processed grains in breads and pasta and many mid- to high-glycemic index foods, even in modest amounts, will cause a high postprandial spike. To keep glucose low and slow, the high fiber carbohydrate are best. I’ve stopped eating dried fruit and eat low glycemic index fresh fruit only in small servings; instead, I fill up with hull-less barley (1), soybeans, legumes, chia seeds, wheat bran, non-starchy vegetables, nuts, seeds, avocado, and seitan.

Tracking daily nutrients on Cronometer.com has been invaluable for meeting the RDA targets. Consequently, my lab results are coming back with great numbers: low cholesterol (high HDL), low inflammation, low blood pressure, normal glucose, and HbA1c at 5.0. This diet works well for me and the other vegans in our group. We’ll continue to monitor our glucose and labs, adjusting when needed, but overall we are quite pleased, as are our doctors, with the outcomes.

Dr. Michael Greger of NutritionFacts.org has released Volume 25 of his Latest in Clinical Nutrition DVD series. This one has a strong focus on digestive ailments. Dr. Greger scours the earth for important studies in peer-reviewed journals…so you don’t have to!

A 2015 study from Italy found that among people attending a gastroenterology clinic complaining of gluten-related symptoms, few actually improved after six months on a gluten-free diet (1).

A total of 392 patients reported gluten-related symptoms upon an appointment at the clinic. Among them, celiac disease was confirmed in 26 and a wheat allergy was confirmed in 2. The remaining 364 were advised to follow–and apparently complied–with a gluten-free diet. After six months, only 27 were symptom-free. The researchers concluded that 86% of people who think they suffer from gluten-related symptoms actually do not.

I have updated the VeganHealth.org article, Calcium and Vitamin D, with a synopsis of the following clinical trial:

“A 2013 study from Germany found that with supplementing daily for 8 weeks at about 2,000 IU, D3 was more effective at raising vitamin D levels (1). The average 25(OH)D levels increased 46 nmol/l in the D3 group (for an average of 89 nmol/l) but only 30 nmol/l in the D2 group (for an average of 68 nmol/l). Vitamin D2 supplementation appeared to decrease the amount of circulating vitamin D3. PTH levels were not different between groups. Because D2 raised levels into the recommended range (50 – 125 nmol/l), it seems preliminary to assume that D3 is more healthy based on these results, though evidence is mounting that D3, even at smaller doses, can raise vitamin D levels higher or more quickly than D2.”

I don’t think this has any health implications for most vegans. If you have experienced a stubborn vitamin D deficiency, it adds some credence to the idea that you should try vitamin D3. Vegan vitamin D3 is available.

In the past year or so, two comprehensive books on plant-based eating have been published by colleagues of mine–Becoming Vegan: Comprehensive Edition by Brenda Davis and Vesanto Melina and The Vegiterranean Diet by Julieanna Hever. Both books deserved a more timely review, but I figure it’s better late than never.

As the title suggests, The Vegiterranean Diet examines the Mediterranean diet–for which there is much compelling evidence–and how it might apply to vegetarian eating. As it turns out, it applies quite well. This would be a great book to give to a family member who is suffering from type 2 diabetes, cardiovascular disease, or obesity due to poor eating habits. In addition to the nutrition information, there are over 60 recipes and many tips on weight loss which I found sensible.

I have updated the article, Calcium and Vitamin D, to reflect recent research showing that vitamin D supplements are better absorbed when taken with meals that contain fat.

The study was a randomized controlled trial conducted at Tufts University (1). It compared taking a 50,000 IU dose of vitamin D3 with three different meals: 1) a fat-free meal, 2) a 30% fat meal with high polyunsaturated fats, 3) a 30% fat meal with high monounsaturated fats. To make a short story even shorter, the meals with fat increased vitamin D absorption 32% over the meals without. There was no difference between meals high in polyunsaturated and monounsaturated fats.

A reader informed me that amaranth was a good source of protein–better than quinoa even. So I checked it out and found that she was correct.

Amaranth has 9 g of protein per cup (cooked) which is slightly higher than quinoa. One cup of cooked amaranth has 250 calories while one cup of cooked quinoa has 222 calories. This gives them about the same amount of protein per calorie.

Amaranth also has a decent amount of lysine, comparable to a serving of soy or other legumes.

Summary Results from Adventist Health Study-2 show vegans to have a 16% lower risk of colorectal cancer than non-vegetarians, but the finding wasn’t statistically significant. Pesco-vegetarians had the lowest rate of all.

EPIC-Oxford and Adventist Health Study-2 (AHS-2) are the two ongoing studies of diet and disease that contain a large number of vegans. This past week, AHS-2 released a report on colorectal cancer rates among various diet groups (1).

In summarizing the research on diet and colorectal cancer to date, the researchers write:

“Among dietary factors thought to influence risk, the evidence that red meat, especially processed meat, consumption is linked to increased risk and that foods containing dietary fiber are linked to decreased risk has been judged to be convincing. The evidence for a link to decreased risk has been judged as probable for garlic, milk, and calcium. Evidence for other dietary components is considered limited.”

Because of the link with red and processed meat, nutritionists had expected that vegans and vegetarians would have a lower risk for colorectal cancer. To date, EPIC-Oxford has not shown a lower risk for vegetarians (results can be seen in Cancer, Vegetarianism, and Diet).

Better news comes from the latest AHS-2 report. After an average follow-up of 7.3 years, the lacto-ovo vegetarians and vegans had a lower risk of colorectal cancer (18% and 16% respectively), but the findings were not statistically significant. Here are the risk ratios and confidence intervals for each group:

Non-Veg

1.00

Semi-Veg

.92 (.62, 1.37)

Pesco

.57 (.40, .82)

Lacto-ovo

.82 (.65, 1.02)

Vegan

.84 (.59-1.19)

The only group with a statistically significant lower risk was the pesco-vegetarians (who eat no meat other than fish), with a 43% lower risk that was highly statistically significant. Despite this, the difference between the pesco-vegetarians and vegans was not statistically significant, though close (.68, .43-1.08).

When lumping all the groups together (semi-, pesco-, lacto-ovo, and vegan) and comparing to non-vegetarians, the “vegetarians” had a statistically significant, 22% lower risk of colorectal cancer (.78, .64-.95).

Overall, colorectal cancer rates in AHS-2 were lower than the population at large and AHS-2 non-vegetarian eat very little meat (54.5 g/d or just 4.5 servings per week).

Could a higher calcium intake for vegans lower their risk of colorectal cancer? In AHS-2, the vegans had slightly lower calcium intakes (801 mg/day) than the pesco-vegetarians (913 mg/day) and non-vegetarians (882 mg/day). But in EPIC-Oxford, where the results were not as positive for vegetarians, vegans had much lower calcium intakes (583 mg/day compared to 1,005 mg/day for non-vegetarians) (2).

Another difference between the EPIC-Oxford and AHS-2 groups is that the AHS-2 vegans had a substantially greater intake of both dietary fiber and vitamin C.

Does eating fish protect against colorectal cancer? The researchers write, “The existing literature provides some, although inconsistent, support for a possible protective association for fish consumption, particularly for rectal cancer; evidence for omega-3 fatty acid consumption is limited and inconsistent.” In other words, it’s not clear.

In summary, colorectal cancer rates in vegans in AHS-2 are promising, but it might be important for vegans to follow calcium recommendations not only for bone health but also to prevent colorectal cancer.